md/raid5: allow removal for failed replacement devices.

Enhance raid5_remove_disk to be able to remove ->replacement
as well as ->rdev.

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 32 insertions, 26 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 2ae63c5b1c25..e5795d39d418 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5086,36 +5086,42 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
         struct r5conf *conf = mddev->private;
         int err = 0;
         int number = rdev->raid_disk;
+        struct md_rdev **rdevp;
         struct disk_info *p = conf->disks + number;
 
         print_raid5_conf(conf);
-        if (rdev == p->rdev) {
-                if (number >= conf->raid_disks &&
-                    conf->reshape_progress == MaxSector)
-                        clear_bit(In_sync, &rdev->flags);
+        if (rdev == p->rdev)
+                rdevp = &p->rdev;
+        else if (rdev == p->replacement)
+                rdevp = &p->replacement;
+        else
+                return 0;
 
-                if (test_bit(In_sync, &rdev->flags) ||
-                    atomic_read(&rdev->nr_pending)) {
-                        err = -EBUSY;
-                        goto abort;
-                }
-                /* Only remove non-faulty devices if recovery
-                 * isn't possible.
-                 */
-                if (!test_bit(Faulty, &rdev->flags) &&
-                    mddev->recovery_disabled != conf->recovery_disabled &&
-                    !has_failed(conf) &&
-                    number < conf->raid_disks) {
-                        err = -EBUSY;
-                        goto abort;
-                }
-                p->rdev = NULL;
-                synchronize_rcu();
-                if (atomic_read(&rdev->nr_pending)) {
-                        /* lost the race, try later */
-                        err = -EBUSY;
-                        p->rdev = rdev;
-                }
+        if (number >= conf->raid_disks &&
+            conf->reshape_progress == MaxSector)
+                clear_bit(In_sync, &rdev->flags);
+
+        if (test_bit(In_sync, &rdev->flags) ||
+            atomic_read(&rdev->nr_pending)) {
+                err = -EBUSY;
+                goto abort;
+        }
+        /* Only remove non-faulty devices if recovery
+         * isn't possible.
+         */
+        if (!test_bit(Faulty, &rdev->flags) &&
+            mddev->recovery_disabled != conf->recovery_disabled &&
+            !has_failed(conf) &&
+            number < conf->raid_disks) {
+                err = -EBUSY;
+                goto abort;
+        }
+        *rdevp = NULL;
+        synchronize_rcu();
+        if (atomic_read(&rdev->nr_pending)) {
+                /* lost the race, try later */
+                err = -EBUSY;
+                *rdevp = rdev;
         }
 abort: